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The first thln^ to note Is that there are four very distinctive 

 soil areas In rowa; KarstCBlg Sprlngsjarea of North Eastern Iowa, the 

 Loess Hills of western Iowa, the rolling hills of southern Iowa and 

 the Prairie Pothole area of central and northern Iowa. Each of these 

 areas have distinctive soil, subsoil and parent material differences. 

 The Biq Springs area of northeast Iowa is underlain with limestone 

 and they have sinkhole problems. These sinkholes of course drain 

 directly Into the ground water and they used to be used as convenient 

 dump sights for every thing from junk to raw sewage. The Loess Hills 

 of western Iowa are a wind blown soil with the topsoll sometimes 60 

 feet deep. These soils are naturally very well drained, but very 

 susceptible to erosion. The rolling hills of southern Iowa are 

 relatively well drained with shallow top soils. The Prairie Pothole 

 soils have a very tight subsoil which makes their natural drainage 

 poor. These soils are extremely productive however, when they are 

 properly drained. 



Jerry Hatfield, from the National Soil Tilth Laboratory, told us 

 that water moves vertically fairly quickly to the shallow 3 to 6 foot 

 deep water table. The water then tends to £low horizontally to a 

 streams sand base. This horizontal movement however is very very 

 slow. After he told us this, he continued on to say that this is 

 their understanding of water movement in an isolated simple 

 watershed, but when looking at a complex watershed like the Des 

 Moines River or the Raccoon River, they really don't understand fully 

 the way water moves or doesn't move in the soil. 



